Optional loading grease gun



1962 E. P. SUNDHOLM 3,059,819

OPTIONAL LOADING GREASE GUN Filed Jan. 8, 1959 2 Sheets-Sheet 1 i), i W32 as 25 'll/II III IX r/ uucr Juu" IN WIN TOR:

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United States Patent Office 3,059,819 Patented Get. 23, 1952 3,959,819@PTIONAL LGADING GREASE GUN Edwin P. Sundhohn, Albert City, Iowa FiledJan. 8, 1959, der. No. 785,689 3 Claims. (ill. 222-326) This inventionrelates to an optional loading grease gun, that is, a grease gun whichis adapted for use selectively with both cartridge-packaged greases andbulk-filled greases, including both the pressure and suction filling ofbulk greases.

The use of cartridge-packaged greases in connection with grease guns hasincreased rapidly in recent years, and guns have been provided forutilizing the grease in the cartridge-packaged form. Such grease guns,however, have suffered from the disadvantage that they could not also beused with bulk greases. An effort has therefore been made to provide anoptional loading grease gun which is adapted for use with bothcartridge-packaged greases and bulk-filled greases. Heretofore, thiseffort has only been partially successful, and the problems presentedhave not been completely solved.

The problem discussed above is rendered particularly difiicult becauseof the fact that bulk greases are commonly introduced into grease gunsin a variety of ways. The grease may be loaded by pumping it into thebarrel of the grease gun, or the grease may be sucked into the barrel.In One procedure in common use, the dispensing head is removed from thegrease gun and the forward end of the barrel is inserted in an open pailof grease. The plunger is then slowly withdrawn within the barrel tosuck the grease into the gun. In another procedure, the grease is suckedinto the barrel through an opening in the dispensing head from a specialcontainer which is constructed so that a tight connection can be madebetween the interior of the grease gun and the interior of thecontainer. In connection with the pressure filling method, it is commonto use gun-filling pumps which deliver the grease under pressure, thegrease being introduced through a valve-controlled opening in thedispensing head. Obviously, therefore it is a difficult problem toprovide a grease gun which is adapted for use with cartridge-packagedgreases and which can also be loaded by any of the pressure-filling orsuction-filling procedures just described.

Even if the gun was to be designed only for the use of bulk-filledgreases, the problem is a difficult one where it is desired to be ableto load the gun by both pressure and suction methods. When the plungerof the grease gun is designed so as to create sufiicient suction on thebackstroke for drawing grease into the gun, it tends to perate lesseffectively in the dispensing operation. If the piston is backed with aspring for urging the piston towards the dispensing head, as is usuallydesirable, this may tend to cause the suction-type plunger to moveinwardly without keeping all of the grease ahead of it. A similarproblem is encountered when it is attempted to fill such grease guns bypumping grease into them. The grease which is introduced under pressuretends to force its way past the piston, particularly if the piston isbacked with a string, and the presence of grease in the portions of thegun behind the piston can create unpleasant difiiculties for theoperators of the guns.

It is therefore an object of the present invention to provide a greasegun which substantially overcomes the problems discussed above. A morespecific object is to provide a grease gun which not only can be filledby any of the suction or pressure methods in common use, but which isalso adapted for use with cartridge-packaged greases. Further objectsand advantages will appear as the specification proceeds.

An illustrative embodiment of the present invention is shown in theaccompanying drawings, in which- FIGURE 1 is a side sectional view of agrease gun embodying the present invention;

FIGURE 2 is an enlarged fragmentary side sectional view showing the rearend portion of the grease gun cylinder or barrel of FIGURE 1;

FIGURE 3, an enlarged detail fragmentary side elevational viewillustrating the relationship of the plunger to the grease gun barrel orcylinder when the gun is being used with bulk-filled greases;

FIGURE 4, a sectional plan view taken on line 4-4 of FIGURE 3 andshowing the rear side of the plunger;

FIGURE 5, an enlarged sectional view of the plunger taken on line 55 ofFIGURE 4;

FIGURE 6 an enlarged fragmentary side sectional view of the grease gunof FIGURE 1 showing the rearward portion of the grease gun with theplunger fully withdrawn and locked in the withdrawn position;

FIGURE 7, a transverse sectional view showing the rear end of theclosure cap and taken on line 77 of FIGURE 6;

FIGURE 8 another transverse sectional view taken on line 88 of FIGURE 6showing the relationship of the parts when the plunger is fullywithdrawn;

FIGURE 9 a view showing the forward face of the plunger taken on line9-9 of FIGURE 6; and

FIGURE 10 a fragmentary enlarged side sectional view of the grease gunof FIGURE 1 showing the forward end portion of the grease gun, thesection being taken on a plane turned degrees with respect to the planeof the section of FIGURE 1.

Referring now more specifically to the embodiment shown in the drawings,it can be seen that the grease gun includes a cylindrical greasecontainer 10, a closure cap 11 threadedly connected to the rear of thecontainer, and a grease dispensing head 12 removably mounted on thefront end of the container. Within container 10 is a slidable plungerassembly 13 which is designed, as will subsequently be explained ingreater detail, to create suction within container 10 when withdrawn orto urge grease towards dispensing head 12 when used with eitherbulkfilled greases or cartridge-packaged greases. As shown in FIG. 1, agrease cartridge 14 is positioned within cylinder 10, the cartridgebeing partially filled with grease 15. Behind plunger assembly 13 isprovided a compound spring 16, the construction of which will also befurther discussed in detail. A plunger rod 17 is provided for the manualactuation of plunger assembly 13, the rod being releasably engageablewith the plunger assembly for retractin g, and rotating the assembly.

In accordance with the present invention, the plunger assembly 13provides an annular portion 18 which is adapted for sealing selectivelywith the inner wall of a grease cartridge 14 positioned within container10 or with the inner wall of the container 10. It will be noted that theplunger portion 18 provides a pair of annular blades 18a and 18b one ofwhich extends outwardly and rearwardly and the other of which extendsoutwardly and forwardly, as shown more clearly in FIGURE 5. The plungerportion 18, which provides the blades 18a and 1812, should be formed ofa resilient, flexible material such as a synthetic rubber. It Will beunderstood that the material should be resistant to deterioration onprolonged contact with grease. In the illustration given, plungerportion 18 is integrally connected to a transversely-extending baseportion 19 which provides a central rearwardly-extending hub portion 20that is slidably received on plunger rod 17, while maintaining a sealingengagement therewith. With the construction shown, the annular portion18 and the integral base portion 19 can be conveniently formed by amolding operation. In the illustration given, the base portion 19 islocked between clamping washers 21 and 22. The washers 21 and 22 providea plurality of complementary depressions 21a and 22a which extendthrough openings in the transverse base portion 19 and bear against eachother. These projections may be united by spot welding as indicated inFIGURE 6. The rear washer 21 also provides projections 2112, as shownmore clearly in FIGS. and 8, which interlock with projections on baseportion 19. The outer edge portions 210 and 220 of the washers areturned toward each other to provide a further interlock.

The lower end of plunger rod 17 is provided with an outwardly extendingpin 23. In the operation of the device, pin 23 may be drawn into one ofthe slots 24 between tabs 22b by means of the handle 25 on the rear endof plunger rod 17. The plunger assembly can then be rotated or retractedas desired.

The sleeve 26 encircles plunger rod 17, and has its forward end abuttingrear washer 21 around hub 28. As indicated more clearly in FIGURE 8, theforward end of sleeve 26 is provided with a plurality of outwardlyextending attachment tabs 27 which are spot Welded to rear washer 22.The intermediate portion of sleeve 25 is provided with integralinwardly-extending tabs 28 and 29, as seen more clearly in FIGURES 6 and8, which cooperate to provide complementary bearing surfaces aroundplunger rod 17, thereby assisting in maintaining plunger assembly 13 atright angles to plunger 17 regardless of the position of the plungerassembly or the plunger rod within the grease gun. The rear end ofsleeve 25 provides a pair of arcuate cars 30 and 31. The rear wall ofend cap 11 provides a pair of arcuate slots 32 and 33 which arealignable with ears 30 and 31 and are arranged to cooperate therewith.The ears are undercut as indicated at 34 (FIGURE 6) for interlockingwith raised areas 35 which lie adjacent the ends of slots 32 and 33.Plunger assembly 13 may be drawn rearwardly until the ears 30 and 31extend respectively through slots 32 and 33, and then the plungerassembly can be slightly rotated so that the ears rest on raised areas35 thereby releasably locking the plunger assembly in the withdrawnposition. The plunger can be released by forceably rotating the ears 3%]and 31 in the opposite direction to bring them into alignment with theslots 32 and 33.

In accordance with the present invention, container 18 toward the rearthereof is formed inwardly to provide means for contracting the blades18a and 18b of plunger annular portion 18. Preferably, the inwardlyformed portion of container also provides means for holding the upperend of a grease cartridge in centered relation within the container. Asshown in FIGURES 1, 2 and 6, an inwardly-extending annular wall portion37 is provided toward the rear of container 10. Annular wall portion 37is arranged to depress blades 18a and 18b inwardly to reduce thediameter of the plunger assembly for insertion into the open end of agrease cartridge. More specifically, plunger assembly 13 can be drawninto and through annular container portion 37, thereby reducing thediameter of the contractable plunger portion by depressing blades 18aand 18b inwardly. FIGURE 6 shows the position of the plunger assemblywhen fully withdrawn and ready for insertion into the open end of agrease cartridge. The cartridge is not shown in FIGURE 6, but it wouldoccupy the position indicated in FIGURE 1.

The particular shape of inwardly extending portion 37 as shown in thedrawings has a number of advantages. However, other shapes can be usedwhile still obtaining certain of the benefits of the present invention.As shown more clearly in FIGURES 2 and 6, container portion 37 iscomposed of a forward section 37:11 which provides an inwardlyconverging wall, an intermediate section 37b which provides a wallconcentric with the body of container 10 but spaced inwardly therefrom,and a rearward section 370 which provides a forwardly converging wall.At the inner end of the forwardly converging section 370 A. is provideda shoulder or abutment 3741. This configuration can be achieved by arolling operation wherein a correspondingly shaped mandrel is insertedin the container and rollers are applied to the outside of the containerto form the wall portion 37 against the mandrel.

In the operation of the device, the forward section 37a will depress theblades 18a and 181) as the plunger assembly is withdrawn, permitting theblades to ride through the intermediate section 37b and over theshoulder 370! to the position shown in FIGURE 6. With the plungerassembly locked in this position by means previously described, a greasecartridge having an open rear end is inserted within the cylinder 19through the front end thereof, the dispensing head 12 having beenpreviously removed. When the. grease cartridge is fully inserted it willoccupy the position shown in FIGURE 1 with the rearward end of thecartridge received within the section 37 b, which due to itsconcentricity with the body of cylinder 10 assists in holding the greasecartridge, such as grease cartridge 14, in centered relation within thecylinder 18. It will also be observed that the rear edge of the greasecartridge 14 lies just in front of the shoulder 37d, the shoulder atleast partially overhanging the rear edge of the cartridge to preventthe forward blade 1812 from catching on the rear edge of the cartridgeas the plunger assembly 13 is inserted into the cartridge. The insertioncan then be accomplished by simply releasing the plunger assembly 13 andallowing the spring 16 to move the plunger assembly forwardly. Forwardlyconverging section 37 0 will depress the blade 18]) so that it will rideover shoulder 37d smoothly and into the open upper end of the greasecartridge, and a similar action will then follow with respect to therearward blade 18a. The position of the plunger assembly 13 within thegrease cartridge is illustrated in FIG- URE l where the cartridge isshown partially filled with grease, as it would appear during the use ofthe gun when part of the grease has been dispensed.

The construction and operation of dispensing head 12 is described moreparticularly in my copending application Serial No. 669,115, filed July1, 1957, now Patent No. 2,923,443. For the purpose of this applicationit is believed suflicient to note that the dispensing head 12 includes abody 38 having a bore 39 therein for slidably receiving piston plunger40 that extends outwardly beyond body 38 and is pivotally connected toan operating handle 41. The forward end of operating arm 41 is pivotallyconnected to a pair of links 42 (FIGURE 10), which in turn are pivotallymounted on body 38, thereby permitting piston 40 to be reciprocated bythe corresponding reciprocation of arm 41. The bore 49 communicates withan inlet opening 43 which extends through cap 44 and the adjacent wallof body 38 to provide for communication between bore 39 and the interiorof container 10 when the piston rod 40 is withdrawn sufficiently touncover inlet opening 43. Body 38 also provides an opening 45communicating with the end of bore 39 towards which piston rod 40advances. A grease discharge fitting 46 is thrcadedly received within anenlarged outer portion of opening 45 and provides a passage 47therethrough for the outflow of grease from within bore 39. Fitting 47provides a spring biased check valve 48 which is arranged to permitoutflow only through passage 45. As shown in FIGURE 1, the outer end offitting 46 is adapted to receive a grease applicator pipe 49. As shownin FIGURE 10, the cap 44, which is threadedly connected to the front endof container 10, also provides an inlet opening 50. In the illustrationgiven, opening 50 is internally threaded to receive a filler fitting 51and thereby mount the same on the outside of head 12 to provide apassage 52 extending from the outside to the inside of container 10.Preferably, fitting 51 includes a sp'ring biased check valve 53 arrangedto permit only inflow through passage 52. It will be noted that theouter portion of fitting 51 which encloses valve 53 is removable fromthe inner portion, being threadedly connected thereto at 54. With thisconstruction, grease can be pumped into container 10 through fitting 51.When it is desired to suck grease into container 10, this can be done byremoving the outer portion of fitting 51 which includes valve 53, andconnecting the remaining portion of fitting 51 to the container fromwhich the grease is to be obtained. Alternatively, dispensing head 12can be removed, and the forward end of container 10 can be applieddirectly to the grease. In either case, the plunger assembly 13 will bein its forwardmost position within the container 16) at the start of thefilling operation, and will be slowly drawn rearwardly to create thesuction within the container for drawing in the grease. The plungerassembly may also be in its forwardmost position when grease is beingpumped into the container since the grease will force the plungerassembly rearwardly until the container is filled with grease.

It is preferred to provide spring means for urging the plunger assemblytoward the forward end of the gun, and the specific spring meansillustrated in the drawings has a number of advantages. The use of acompound spring, such as spring 16 permits the entire spring to bewithdrawn within the rear cap 11 when the plunger assembly is in itsrearwardmost position, as indicated in FIGURE 6, while still providingsufiicient spring action during the last portion of the forward movementof the plunger a sembly.

In the illustration given, the spring means 16 includes two coil springsections 16a and 1612. Section 1612 is of smaller diameter than section16a and is arranged to telescope within section 16a. The forward endportion of section 16a and the rearward end portion of section 16b areinterconnected in overlapping relationship by means of a sleeve 160 asshown more clearly in FIGURES 6 and 8. The forward end of section 16bbears against rear washer 21 of plunger assembly 13, and the rearwardend of section 16a bears against the inside of the rear wall of cap 11.The projections 21b of rear washer 21 assist in centering the forwardend of spring section 16b.

While in the foregoing specification the various features of the presentinvention have been described with relation to a specific embodimentthereof, as shown in the grease gun of the accompanying drawing, it willbe apparent to those skilled in the art that the features of the presentinvention are adapted for use in grease guns which differ inconstruction from the one shown in the drawing.

I claim:

1. In a grease gun adapted for use selectively with cartridge-packagedgreases and for both pressure and suction filling of bulk greases, saidgrease gun being of the kind having a cylindrical grease container withan integral wall, a closure cap removably mounted on the rear of saidcontainer, a grease dispensing head removably mounted on the front ofsaid container, and a slidable plunger assembly within said container,the combination comprising a pair of annular blades of resilient,flexible material provided by said plunger assembly for sealinglyengaging the inner wall of said grease container, one of said annularblades extending outwardly and rearwardly and the other of said bladesextending outwardly and forwardly, the integral wall of said containertoward the rear of said container being formed inwardly from theexterior thereof and providing an integral annular wall portion ofgreater inward extent than the wall of said container extendingforwardly therefrom, said annular wall portion having at least a forwardsection and a rearward section, said forward section providing aninwardly converging surface merging smoothly at its forward end with theinside surface of said container wall, means for retracting said plungerassembly into the rearward portion of said container, said plungerassembly being retractable to a position where both of said annularblades are located rearwardly of the said forward section of saidannular wall portion and adjacent the said rearward section thereof,said blades being depressable inwardly by engagement with said forwardsection to reduce the diameter of said plunger and being held in saiddepressed condition by said rearward section, and means for releasablylocking said plunger assembly in said retracted position, whereby uponwithdrawal behind the forward section of said annular wall portion saidblades can be inserted in the open rear end of a grease cartridge.

2. The combination of claim 1 wherein said annular Wall portion also hasan intermediate section providing an inner surface concentric with theinner surface of the forwardly extending portion of said container wallbut spaced inwardly therefrom for holding the upper end of a greasecartridge in centered relation within said container, said intermediatesection being located between said forward section and said rearwardsection.

3. The combination of claim 1 wherein said annular wall portion of saidcontainer also has an intermediate section providing an inner surfaceconcentric with the inner surface of the forwardly-extending portion ofsaid container wall but spaced therefrom for holding the upper end of agrease cartridge in centered relation within said container, saidintermediate section being located between said forward section and saidrearward section, and wherein said annular wall portion also provides aninwardly-projecting annular abutment located at the rearward end of saidinner concentric surface in front of said rearward section for engagingthe rear edge of a grease cartridge.

References Cited in the file of this patent UNITED STATES PATENTS1,122,111 Hanson Dec. 22, 1914 1,472,123 Heinitsh et al. Oct. 30, 19231,702,619 Sargent Feb. 19, 1929 1,729,219 Kellogg Sept. 24, 19291,854,458 De Quincy et al Apr. 19, 1932 2,174,421 Krannak Sept. 26, 19392,361,126 Klein Oct. 24, 1944 2,612,296 Campbell et a1 Sept. 30, 19522,635,787 Bryant Apr. 21, 1953 2,759,640 Deupree Aug. 21, 1956 2,792,972Deupree May 21, 1957 2,886,215 Klein et al. May 12, 1959 2,915,226Sundholm Dec. 1, 1959 2,941,854 Jernander June 21, 1960

